1. Field of the Invention
The present invention relates in general to power lid closing devices for motor vehicles and more particularly to power lid closing devices for closing a lid, such as a trunk lid or the like, by the force of an electric power. More specifically, the present invention is concerned with power lid closing devices of a type which comprises a lid drawing mechanism mounted on a trunk structure of a vehicle body and an electric power unit coupled with the lid drawing mechanism for powering the same, wherein when a trunk lid is manually pivoted down to an almost closed position, the lid drawing mechanism catches the trunk lid and enforcedly pulls down the same to the fully closed position.
2. Description of the Prior Art
In order to clarify the task of the present invention, one conventional power lid closing device of the above-mentioned type will be described with reference to FIGS. 28 to 31, which is shown in Japanese Patent First Provisional Publication 4-302683.
As is understood from FIGS. 28 and 29, the conventional power lid closing device comprises a motor mounting plate 1 and a cover base plate 2 which face each other to define therebetween a space. As is seen from FIG. 29 a latch base plate 3 is installed in the space and has one end pivotally supported. The motor mounting plate 1 carries thereon an electric motor 4 (see FIG. 28) and a speed reduction gear 5. An output shaft 5a of the speed reduction gear 5 is projected into the space between the motor mounting plate 1 and the cover base plate 2. As is best seen from FIG. 30, the output shaft 5a has at a leading end thereof a connecting pin 5b connected thereto. As will be seen from FIG. 31, the cover base plate 2 is provided near the output shaft 5a of the speed reduction gear 5 with an output shaft 7 of a driving mechanism 6 by which the latch base plate 3 is pivoted. As is seen from FIG. 29, a leading end of the output shaft 7 is formed with an engaging groove 7a with which the connecting pin 5b of the output shaft 5a is engaged. Thus, the output shaft 5a and the other output shaft 7 can rotate like a unit. Because of a so-called "joint mechanism" provided by both the connecting pin 5b and the engaging groove 7a, the connection of the output shaft 5a to the output shaft 7 is achieved with ease. That is, even though a slight displacement is present between these two output shafts 5a and 7 upon assembly, operative connection is achieved therebetween. As is seen from FIG. 30, the output shaft 5a of the speed reduction gear 5 has a sector cam 8 secured thereto. A limit switch 9 is mounted to the motor mounting plate 1, which has a detecting arm 9a slidably engaged with a cam surface 8 of the sector cam 8. Thus, the angular position of the output shaft 5a of the speed reduction gear 5 can be detected by the limit switch 9. In accordance with information signals issued by the limit switch 9, operation of the electric motor 4 is controlled.
However, in the above-mentioned conventional power lid closing device, the joint mechanism provided by both the connecting pin 5b and the engaging groove 7a is excessively long, which causes a marked increase in thickness of the lid closing device and thus brings about a bulky construction of the same. Furthermore, in the conventional device, the joint mechanism tends to produce a noise due to its inherent construction. Furthermore, in the conventional device, the lid pulling force generated by the device is generally constant and relatively strong throughout the closing stroke for the lid. Thus, if operator's hand or hands are accidentally caught in the lid during closing movement of the lid, he or she can not pull out the hands with ease.